This invention relates generally to the field of hand tools, and more particularly to an apparatus for telescopically extending the shaft length of a tool used for turning a fastener or the like while protecting the critical mechanisms for extending the tool shaft by moving the mechanism inside the handle. An additional feature of the invention is adaptation to use multiple replaceable tool ends for performance of multiple tasks.
All too often, the problem is found in the field, when a user must access a fastener that is in difficult location. Traditionally, a user must have available for ready access tools of multiple lengths. Short tools must be available for working in restricted spaces, long tools must be available for reaching the tool into a restricted space or moving the user away from the fastener.
Short or xe2x80x9cstubbyxe2x80x9d tools are useful and often necessary for working in a confined space, but, suffer from an additional shortcoming of being small and therefore having small handles that are frequently difficult to grasp and apply sufficient torque to the fastener. While longer tools do not suffer the same shortcoming""s as short tools they have there separate problems, including being large and therefore difficult to store.
As a result, most conventional screwdrivers and tool handles are of medium length and perform adequately in most circumstances, but, cannot be used in all circumstances necessitating the user owning and using multiple drivers as the task requires.
The tool industry over the years has innovated new and useful tool designs to meet specific industry requirements for additional tool utility. Tools of multiple functionality have entered the tool industry, and have found valued place in many tool boxes. Telescoping shaft length tools can improve work efficiency by reducing the number of tools of that a user must have available for use. Thus a user can perform more work in a given time.
The invention is to provides a telescoping shank for telescopically extending the length of a screw driver, socket end, or a wrench; making the tool more versatile than existing tools having a smooth, non-threaded shank, which is easy and relatively inexpensive to manufacture. The telescoping mechanisms is housed internally in the tool handle, providing protection to these critical mechanisms, and making the tool more dependable, and of greater utility.
The telescoping of the tool is controlled by a lockable adjustment knob located on the end of a handle so that a user can easily alter the length regardless of the location of the tool. The telescoping shank is nonremovable and can be integrated into a handle minimizing the size of the tool while protecting the adjustment mechanism.
An apparatus for telescopically extending the shaft length of a tool, comprising: a handle with a circular or noncircular hollow core shaft with at least one longitudinal channel in combination with a hollow shank with circular or noncircular cross section, with integral, internally threaded drive ring on one end. The drive ring has at least one associated tab for insertion into the longitudinal channel. The second shank end has a head assembly to receive screw driver, socket, or wrench tool fittings. Circular shaft and shank cross sections are associated with the screw driver or socket configuration, in addition, a noncircular or elliptical cross section is associated with a wrench configuration. An externally threaded adjusting rod engages the threaded drive ring, and extends into the hollow shank. A rotatable adjusting knob is attached to the adjusting rod. A lock mechanism which is integral to the adjusting knob attached to the handle which is used to selectively eliminate rotation of the knob. The lock assembly comprises a first friction washer attached to the knob and a second friction washer attached to the handle wherein the washers engage each other to prevent rotation of the knob. Alternatively, the lock assembly comprises a first splined portion attached to the knob and a second splined portion attached to the handle wherein the portions engage each other. A spring, and spring retainer system is attached to the adjusting rod to provide engaging force on the splined portions. A key is attached to the adjusting rod as a means of transferring rotational force between the adjusting knob and the adjusting rod.